Sensors have been developed for sensing or measuring various types of physical and chemical parameters. Differential capacitance detectors are among the technologies that have been developed.
Ion sensitive field effect transistor (ISFET) based sensors are commonly employed for sensing biochemical reactions. Changes in conductance within a test solution can be detected from changes in transistor conductance. For example, an ISFET sensor may be employed to detect the release of hydrogen as the byproduct of DNA base pairing. ISFET technology however presents various challenges, one of which is flicker (1/f) noise that is the dominant noise source in field-effect transistors. As the transistor dimensions are shrunk to improve the array density, the flicker noise intensity increases, hence limiting the resulting signal-to-noise ratio and scaling up the array density.